Ambulatory blood pressure and physical activity in heart failure

Background. Ambulatory blood pressure (ABP) measurement is a means of monitoring cardiac function in a noninvasive way, but little is known about ABP in heart failure (HF) patients. Blood pressure (BP) declines during sleep as protection from consistent BP load, a phenomenon termed "dipping." The aims of this study were (1) to compare BP dipping and physical activity between two groups of HF patients with different functional statuses and (2) to determine whether the strength of the association between ambulatory BP and PA is different between these two different functional statuses of HF. ^ Methods. This observational study used repeated measures of ABP and PA over a 24-hour period to investigate the profiles of BP and PA in community-based individuals with HF. ABP was measured every 30 minutes by using a SpaceLabs 90207, and a Basic Motionlogger actigraph was used to measure PA minute by minute. Fifty-six participants completed both BP and physical activity for a 24-hour monitoring period. Functional status was based on New York Heart Association (NYHA) ratings. There were 27 patients with no limitation of PA (NYHA class I HF) and 29 with some limitation of PA but no discomfort at rest (NYHA class II or III HF). The sample consisted of 26 men and 30 women, aged 45 to 91 years (66.96 ± 12.35). ^ Results. Patients with NYHA class I HF had significantly greater dipping percent than those with NYHA class II/III HF after controlling their left ventricular ejection fraction (LVEF). In a mixed model analysis (PROC MIXED, SAS Institute, v 9.1), PA was significantly related to ambulatory systolic and diastolic BP and mean arterial pressure. The strength of the association between PA and ABP readings was not significantly different for the two groups of patients. ^ Conclusions. These preliminary findings demonstrate differences between NYHA class I and class II/III of HF in BP dipping status and ABP but not PA. Longitudinal research is recommended to improve understanding of the influence of disease progression on changes in 24-hour physical activity and BP profiles of this patient population. ^ Key Words. Ambulatory Blood Pressure; Blood Pressure Dipping; Heart Failure; Physical Activity. ^

AROUSAL, FATIGUE AND MENTAL PERFORMANCE: THE EFFECTS OF FASTING ON COGNITION

This study examined the effects of skipping breakfast on selected aspects of children's cognition, specifically their memory (both immediate and one week following presentation of stimuli), mental tempo, and problem solving accuracy. Test instruments used included the Hagen Central/Incidental Recall Test, Matching Familiar Figures Test, McCarthy Digit Span and Tapping Tests. The study population consisted of 39 nine-to eleven year old healthy children who were admitted for overnight stays at a clinical research setting for two nights approximately one week apart. The study was designed to be able to adequately monitor and control subjects' food consumption. The design chosen was the cross-over design where randomly on either the first or second visit, the child skipped breakfast. In this way, subjects acted as their own controls. Subjects were tested at noon of both visits, this representing an 18-hour fast.^ Analysis focused on whether or not fasting for this period of time affected an individual's performance. Results indicated that for most of the tests, subjects were not significantly affected by skipping breakfast for one morning. However, on tests of short-term central and incidental recall, subjects who had skipped breakfast recalled significantly more of the incidental cues although they did so at no apparent expense to their storing of central information. In the area of problem-solving accuracy, subjects skipping breakfast at time two made significantly more errors on hard sections of the MFF Test. It should be noted that although a large number of tests were conducted, these two tests showed the only significant differences.^ These significant results in the areas of short-term incidental memory and in problem solving accuracy were interpreted as being an effect of subject fatigue. That is, when subjects missed breakfast, they were more likely to become fatigued and in the novel environment presented in the study setting, it is probable that these subjects responded by entering Class II fatigue which is characterized by behavioral excitability, diffused attention and altered performance patterns. ^

Mechanism of subunit interaction and DNA binding of the heterotrimeric CCAAT binding factor CBF

Many eukaryotic promoters contain a CCAAT element at a site close ($-$80 to $-$120) to the transcription initiation site. CBF (CCAAT Binding Factor), also called NF-Y and CP1, was initially identified as a transcription factor binding to such sites in the promoters of the Type I collagen, albumin and MHC class II genes. CBF is a heteromeric transcription factor and purification and cloning of two of the subunits, CBF-A and CBF-B revealed that it was evolutionarily conserved with striking sequence identities with the yeast polypeptides HAP3 and HAP2, which are components of a CCAAT binding factor in yeast. Recombinant CBF-A and CBF-B however failed to bind to DNA containing CCAAT sequences. Biochemical experiments led to the identification of a third subunit, CBF-C which co-purified with CBF-A and complemented the DNA binding of recombinant CBF-A and CBF-B. We have recently isolated CBF-C cDNAs and have shown that bacterially expressed purified CBF-C binds to CCAAT containing DNA in the presence of recombinant CBF-A and CBF-B. Our experiments also show that a single molecule each of all the three subunits are present in the protein-DNA complex. Interestingly, CBF-C is also evolutionarily conserved and the conserved domain between CBF-C and its yeast homolog HAP5 is sufficient for CBF-C activity. Using GST-pulldown experiments we have demonstrated the existence of protein-protein interaction between CBF-A and CBF-C in the absence of CBF-B and DNA. CBF-B on other hand, requires both CBF-A and CBF-C to form a ternary complex which then binds to DNA. Mutational studies of CBF-A have revealed different domains of the protein which are involved in CBF-C interaction and CBF-B interaction. In addition, CBF-A harbors a domain which is involved in DNA recognition along with CBF-B. Dominant negative analogs of CBF-A have also substantiated our initial observation of assembly of CBF subunits. Our studies define a novel DNA binding structure of heterotrimeric CBF, where the three subunits of CBF follow a particular pathway of assembly of subunits that leads to CBF binding to DNA and activating transcription. ^

Mechanism of mRNA stability control mediated by AU -rich element: Characterization of cis-elements and trans-factors

Regulation of cytoplasmic deadenylation, the first step in mRNA turnover, has direct impact on the fate of gene expression. AU-rich elements (AREs) found in the 3′ untranslated regions of many labile mRNAs are the most common RNA-destabilizing elements known in mammalian cells. Based on their sequence features and functional properties, AREs can be divided into three classes. Class I or class III ARE directs synchronous deadenylation, whereas class II ARE directs asynchronous deadenylation with the formation of poly(A)-intermediates. Through systematic mutagenesis study, we found that a cluster of five or six copies of AUUUA motifs forming various degrees of reiteration is the key feature dictating the choice between asynchronous versus synchronous deadenylation. A 20–30 nt AU-rich sequence immediately 5 ′ to this cluster of AUUUA motifs can greatly enhance its destabilizing ability and is an integral part of the AREs. These two features are the defining characteristics of class II AREs. ^ To better understand the decay mechanism of AREs, current methods have several limitations. Taking the advantage of tetracycline-regulated promoter, we developed a new transcriptional pulse strategy, Tet-system. By controlling the time and the amount of Tet addition, a pulse of RNA could be generated. Using this new system, we showed that AREs function in both growth- and density-arrested cells. The new strategy offers for the first time an opportunity to investigate control of mRNA deadenylation and decay kinetics in mammalian cells that exhibit physiologically relevant conditions. ^ As a member of heterogeneous nuclear RNA-binding protein, hnRNP D 0/AUF1 displays specific affinities for ARE sequences in vitro . But its in vivo function in ARE-mediated mRNA decay is unclear. AUF1/hnRNP D0 is composed of at least four isoforms derived by alternative RNA splicing. Each isoform exhibits different affinity for ARE sequence in vitro. Here, we examined in vivo effect of AUF1s/hnRNP D0s on degradation of ARE-containing mRNA. Our results showed that all four isoforms exhibit various RNA stabilizing effects in NIH3T3 cells, which are positively correlated with their binding affinities for ARE sequences. Further experiments indicated that AUF1/hnRNP D0 has a general role in modulating the stability of cytoplasmic mRNAs in mammalian cells. ^

IL -24; a glycosylated dimeric cytokine affecting monocytes and cytotoxic to melanoma cells

IL-24 is an unusual member of the IL-10 family, which is considered a Th1 cytokine that exhibits tumor cell cytotoxicity. I describe the purification of this novel cytokine from the supernatant of IL-24 gene transfected human embryonic kidney cells and define the biochemical and functional properties of the soluble, human IL-24 protein. ^ I showed IL-24 non-covalently associates with bovine albumin. Immunoaffinity purification followed by cation exchange chromatography resulted in the significant enrichment of N-glycosylated IL-24. This protein elicited dose-dependent secretion of TNF-α and IL-6 from purified human monocytes and TNF-α secretion from PMA differentiated U937 cells. I showed this same protein was cytotoxic to melanoma tumor cells via the induction of IFN-α. ^ I reported IL-24 associates as at least two disulfide linked, N-glycosylated dimers. Enzymatic removal of N-linked-glycosylation from purified IL-24 partially diminished its cytokine and cytotoxic functions. Disruption of IL-24 dimers via reduction and alkylation of intermolecular disulfide bonds nearly abolished IL-24s cytokine function. ^ I elucidated IL-24 induced TNF-α secretion was pSTAT1, pSTAT3 as well as the class II heterodimeric receptors IL-20R1/IL-22R2 independent. I identified a requirement for the heterodimer of Toll-like Receptors 1 and 2 for IL-24s cytokine function and show a physical interaction between IL-24 and the extracellular domain of TLR-1. ^ Thus, I demonstrated that purified N-glycosylated, soluble, dimeric, human IL-24 exhibits both immunomodulatory and anti-cancer activities and these functions remain associated during purification. IL-24 induced TNF-α secretion required an interaction with the heterodimeric receptor TLR-1/2 and IL-24s cytotoxic affect to melanoma tumor cells was in part due to its induction of IFN-β. ^

Spicule dimensions of Siphonodictyon spp., raw data, biometry and frequency distributions

Early descriptions for species of Aka were poor in detail, and the only spicule type that occurs in this genus does not vary much between species, which led to taxonomic confusion. Moreover, the type specimens of 5 species of Aka are lost, causing considerable problems. Mediterranean specimens of Aka were identified as Aka labyrinthica (Hancock, 1849) by Topsent (1900), even though this species was originally described from the Indo-Pacific. All following publications on Mediterranean Aka accepted Topsent's decision. We assessed this problem with new samples from the Ionian Sea. Our material consisted of only one specimen of Aka, and we had to rely mainly on spicule characters for comparison to other species. We developed a system for species recognition solely based on spicular characters and biometry, involving a combination of the parameters oxea length, width, tip form and angle of curvature. This approach was surprisingly accurate. Forming ratios of the above parameters was less helpful, but can sometimes provide additional information. We identified our sample as Aka infesta (Johnson, 1899), and describe it as a minute-fistulate species with large, multicamerate erosion traces and stout, smooth oxeas. Our data further imply that A. labyrinthica sensu Hancock has not yet been found in the Mediterranean. A. labyrinthica sensu Topsent is a collection of different species not including A. labyrinthica sensu Hancock.